[Kenwood] FW: [ts-940] Advice on what to do upgrade TS-940 Power Supply

[Jeff King]

I have been fixing some old parts in my 940 so it will run another 20 
years.

I heard the power supply is a weak point, but only saw one post on that 
which is attached below. I would like any advice on what to do upgrade
the supply.

I looked at the AVR Board and D1, D2, D10-D13 all look like they have 
been running hot.

Existing U058 are 100V 2.5A. (0.25KW)
Seems like replacing theme with 1N5404s which are 400V 3A (1.2KW)would 
be a safe idea. Any opinions advice on whether the 1N5404 is a suitable 
replacement part?

>From below:
"Replace the power supply pass transistors with 2N5886 preferably from 
ON"
Semiconductor 
Is this a good idea?
Existing 2N5885s ARE 60V 25A
2N5886s are 80V 25A.

>From below:
"Change all the zener diodes on the AVR board to 1 watt units"

There is is only one zener diode [S15VB10] and it is off the AVR
What is a suitable replacement for the S15VB10?

Any advice appreciated.

Yours sincerely
Jeff King ZL4AI



From: John [hydroaction at cfl.rr.com]
Sent: Saturday, 10 April 2004 15:36
To: ts-940 at yahoogroups.com
Subject: Re: [ts-940] Any problems to look for??
Replace the power supply pass transistors with 2N5886 preferably from ON
Semiconductor and change all the zener diodes on the AVR board to 1 
watt units...If
your 7 mil 940 still has the original 2N5885 pass transistors in 
it ....You have a
disaster that will happen .....






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